1. Field of the Invention
The present invention relates generally to the treatment of cell proliferative diseases such as cancer. More particularly, it concerns tyrphostin and tyrphostin-like compounds useful for the treatment of cell proliferative diseases such as cancer, methods of synthesis of these compounds, and methods of treatment employing these compounds.
2. Description of Related Art
AG490 is a kinase inhibitor that inhibits Jak2/Stat3 signaling. Targeted inhibition of the Jak/Stat pathway with AG490 inhibits tumor cell growth and increases sensitivity to apoptotic stimuli; thus, inhibitors of this pathway likely represent potential therapeutics for cancer therapy (Catlett-Falcone et al., 1999; Alas and Bonavida, 2003; Burdelya et al., 2002). Because IL-6 promotes survival and proliferation of certain cancerous cell lines through the phosphorylation of STAT3 (Bharti et al., Verma et al., Kerr et al.), kinase inhibitors similar to AG490 have potential as anti-cancer drugs.
AG490 is structurally classified as a tyrphostin. U.S. Pat. No. 6,596,828B2 and U.S. patent application 2003/0013748 describe compounds that have structural similarity with AG490.
Unfortunately, AG490 has limited activity in animal studies and must be used at high concentrations (˜50 to 100 μM) to achieve inhibition of Jak2/Stat3 signaling and anti-tumor effects, and this low potency of AG490 is insufficient to warrant clinical investigation of this compound for the treatment of cancer (Burdelya et al., 2002; Meydan et al., 1996; Constantin et al., 1998). Thus a need exists for therapeutics that exhibit strong anti-proliferative effects through a similar mechanism at lower therapeutic concentrations.